In particular in the case of small filling amounts, for example pharmaceutical powders or the like, it is not only difficult to perform exact and reproducible dosing, but it is also difficult to quantitatively determine or check the dosed and filled masses.
The use of X-ray devices for in-process filling control is known in principle. However, the use is associated with a series of problems. An X-ray image chain is relatively unstable compared to optical industrial cameras. Fluctuations in terms of brightness, spectral distribution and imaging geometry are relatively pronounced. Automated interpretation of the X-ray results is therefore possible in the prior art only to a limited extent, which consequently entails two different scenarios. In a first scenario, non-metallic packages, which are highly transmissive for X-rays, are X-rayed. The resulting X-ray signature can have a sufficiently fine resolution for allowing the performance of a quantitative mass determination of the content. In a second scenario, packages having one or more metallic foil layers are X-rayed. Such packages, for example from aluminum foil, have a very pronounced absorption effect for the X-rays passing through them, which is significantly higher than the absorption effect of the generally non-metallic package content. The signature of the X-ray image is thus dominated by the metallic foil and is influenced only to a comparatively small degree by the package content. The X-ray result therefore at best permits qualitative statements, which means statements as to whether a filling is present or not. Due to the pronounced shielding effect of the metallic foil, it is practically impossible to make quantitative statements, that is, statements regarding the amount of the filling mass. In simple terms, it is possible to determine whether the metallic foil package contains a filling, but not whether the filling exhibits deviations from the desired target mass.